Electrical condenser



Dec. 10, 1929.

Y C. $NELL ELECTRICAL CONDENSER Filed May 19, 1923 Patented Dec. 10, 1929 UNITED STATES PATENT OFFICE JAMES C. SNELL, E OAK PARK, ILLINOIS, ASSIGNOR TO PREMIER ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, CORPORATION OF ILLINOIEi ELECTRICAL CONDENSER Application filed May 19,

The invention relates to electrical condenser-s. Adjustable condensers, as heretofor-e constructed, included a series of stationary and an adjustable series of movable plates interleaved with the plates of the stationary series and capable of con o1nt rotation to quickly vary the capacity value of the instrument and additionally a small series to effect a fine adjustment to the precise capacity value desired.

The object of the present invention is to dispense with plural series of separately adjustable plates, while retaining provision for the fine adjustment desired. This ob]ect is attained primarily by providing means for directly rotating the entire series of movable plates and means for rotating them through a speed reducing device toeffect the fine adjustment desired.

Other objects of the invention will appear from the description.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings: Fig. 1 is a front elevation of a condenser embodying the invention. Fi 2 is a plan. Fig. 3 is a section taken on line 33 of Fig. 1. Fig. 4 is a section on line t4 of Fig. 3. Fig. 5 is a transverse section on line 55 of Fig. 3.

The invention is exemplified in a cone denser comprising a series of stationary substantially semi-circular plates 8 and a series of rotatable plates 7 interleaved with the stationary plates and also substantially semicircular in form. The stationary plates are secured on rods 9, 10, 11, suitable spacing washers 12 being interposed between contiguous plates. Said rods are secured in front and rear supporting plates or members 13 and 14. The spacing washers and plates serve to space the supporting plates 13 and 14 and the latter are held by clamp-screws 16 on the ends of the rods respectively. Plates 13and 14 and said rods constitute a supporting frame for the stationary plates and also for the rotatable plates. This frame is secured to a support 17 by screws 18 which extend through said support and into sockets 1923. Serial No. 640,019.

19 fixed on the front face of frame-plate 13. This frame is formed of suitable conducting material and a conductor 20 is connected to a terminal 22 which is clamped to frameplate 14. by the nut 16 on the rear end of rod 9. The stationary plates are electrically connected through washers 12, rods 9, 10 and 11 and frame-plate 14 to the conductor terminal 22.

A sleeve or hollow shaft 24 is rotatably supported but insulated from frame-members 13 and 14. Plates 7, with spacing-wash ers 25 between them, are longitudinally clamped on said. sleeve by the nuts 26 and 27. A. conductor strip 28 is insulated from frame plate 14 by a strip 29 and is securedto said plate by a screw 30 which is also insulated from plate 14 and provided with a nut 31 for clamping a terminal strip 32 against conductor strip 28. The upper end of strip 28 is in electrical contact with sleeve 24, so that therotatable plate 7 will constantly be in electrical communication with the conductor 34 attached to terminal 32 through washers 25, sleeve 24, and strip 28. Insulation 35 is interposed between the frame-plate 13 and sleeve 24 and insulation 86 between said sleeve and frame-plate 14. A handle or finger-piece 37 is secured by a screw 38 to the front end of sleeve 24 which is extended through and to the front of support 17. A dial plate 39 is secured by screws to the inner end of finger-piece 37 and is provided with suitable indications to indicate with the stationary indication 40 the difierent positions of the rotatable series of plates and the corresponding capacity values. F inger-piece 37 exemplifies means for directly and quickly shifting the rotatable plates into approximately the position desired.

To provide for the necessary fine adjustment to bring the movable plates intoposition for the precise capacity value desired, means are provided for shifting the rotatable plates ata reduced speed. This mechanism comprises a member 41 which is fixedly secured on the inner end of sleeve 24 and is provided with-a flared flange 42 having an internal conoidal friction face; a plurality of friction rollers or pulleys 43; a small tapered Wheel or pinion 44; a shaft 45 extending through sleeve 24, and to the inner end of which pinion 44 is fixed; and a handle or finger-piece 46 fixed by screw 47 to the projecting front end of shaft 45. Rollers or Wheels 43 are loosely mounted on studs 48 which are supported by a plate 49 which is held on rods 50 by nuts 51. Rods 50 are fixed to frameplate 14 and springs 52 urge plate 49 against nuts 51 and permit the nuts 51 to be turned to take up the rollers 43 to compensate for any wear in the speed reducing devices. By mounting the rollers 43 loosely on studs 48, the rollers are free to position and adjust themselves between the drive-pinion 44 and the friction I The operation of the improved condenser will be as follows, it being understood that the capacity value of the condenser is varied .or finger-piece 37 for this purpose.

according to the relative position of the rotatable and the stationary series of interleaved plates, viz: VVhena quick or coarse adjustment is desired, the operator will turn finger-piece 37 to rotate the entire series of movable plates to approximately the correct position for the capacity value desired, the plates being directly rotatable by said handle When a finer adjustment is desired, the operator will rotate handle-46 which will operate pinion 44 through shaft 45. The pinion will rotate rollers 43 and the latter will rotate the driven member 41 at a greatly reduced speed with respect to the handle 46. Consequently, a very fine adjustment can be given to member 41 to correspondingly adjust the entire series of the rotatable plates and thus correspondingly vary the capacity values of the condenser. When the handle 37 is turned,

the friction surface on member 41, owing to the inertia of the reduc ng gearing, slips over the rollers43 Without rotating handle 46, so

that the latter will be idle when the handle 3.7.. is rotated for quick adjustment of the rotatable blades.

. The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the ap- 1. In an electrical instrument for controlling or modifying a current, a movable element, a sleeve for moving the element having a .centrally apertured operating knob thereon, a rod extending through the sleeve and apertured knob, a circular pan-like housing secured on the end of said sleeve, a friction pinion on the contiguous end of said rod, and

- friction means between said pinion and said housing for transmitting motion from the rod to the sleeve at reduced speed.

2. An instrument as defined in claim 1 wherein said friction means include a plurality of bevelled pivoted rollers spring pressed into contact between the inside peripheral face of the housing and said friction pinion.

3. An instrument as defined in claim 1 wherein said friction means includes a housing cover spring-pressed in a position to close said housing, and a plurality of bevelled rolleis pivoted to the inside face of said cover to contact between the inner peripheral edge of the housing and the face of said friction pinion.

Signed at Chicago, Illinois this 4th day of May, 1923.

JAMES C. SNELL.

pended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is: g 

